Too much/little head pressure

[Don1]

Lots of information on what to do with too little head pressure. After cleaning everything, reversing the spring and adding a washer on the end seemed to help for me. In fact it helped too much the head pressure was 110 lbs. I took everything apart and assembled it like it was originally and it went down to 98 lbs. I could find nothing on how to reduce the head pressure anywhere. So I found that I could lower it to 1 click, then back it off 1/8 of a turn and it would be in the 75 - 85 lbs that it needed to be.

Inserted the board to be cut and started. 20% into the cut, I got a Y stall error. I took the board out and re checked the head pressure. Now one click got it to 85 lbs. Re inserted the board thinking that as accurate as the machine is it would just go over the pattern without changing anything.

I was mortified to see the bit NOT SPINNING go over the pattern already cut. After 6 or 7 passes the motor kicked in and it was running normally. After 10 minutes it happened again. The bit goes over the already cut portion with out spinning. When I looked, after a while, it started spinning again. I turned everything off, concerned that I might break a bit or something else should this happen while actually carving. Does anybody have any ideas on. (1) how to reduce the head pressure if one does too good a job in adjusting it. (2) Why it would trace the pattern without spinning to start and stop, then start again in the middle.

Thanks.

Don

[chief2007]

On the head pressure he is the manual on how to increase or decrease the head pressure http://www.carvewright.com/assets/service/Service_instructions/CarveWright_service_adjust_head_pressure.pdf.

Also the link to the maintenance requirements http://www.carvewright.com/support-page/maintenance/.

Now to your cut motor issue. It may have simply been that the cut motor switch was not making full contact with the cover tab, and therefore did not come on until the machine basically vibrated enough to make contact.
You can use the user test and sensor checks to make sure the cut motor working and the switches and closing properly.

[Don1]

Chief 2007,

The link http://www.carvewright.com/assets/se...d_pressure.pdf (http://www.carvewright.com/assets/service/Service_instructions/CarveWright_service_adjust_head_pressure.pdf). does not work on any of my browsers. I think it got messed up when they changed their servers. Maybe you got it from your notes.

Thanks for the maintenance guidelines, I have been all over those sections by the end of the day.

Cut motor intermittent cut out. First I took my compressed air and blew out the switch both engaged and not engaged. I used all the checks that you mentioned and they said everything worked. The problem continued. After calling customer support I took the top off and tested the integrity of the switch numerous times (circuit test). It worked every time.

Tomorrow I will be sending in the CPU in the machine and the power pack. ALL the connections were tight when checked.

BTW Why, when I click on Go Advanced, do several words that I have typed all of a sudden have links to sites that I have never heard of?

Thanks.

Don

[chief2007]

Hi Don,

Don't know what to tell you on the the Go Advanced issue, I have never had that happen.

The link I posted for the manual was from the carvewright site. Grabbed it yesterday when I posted it. when I click on it - it opens without problem. As long as you got the info that is what matters.



Steve

[badbert]

CarveWright System Service – Adjusting the Head Pressure (Rev 1.7) 09/30/09 1
Checking and Adjusting the Head Pressure
Cranking the head compression rollers down onto the workpiece assures that there is
sufficient pressure to move the workpiece in and out of the machine on the traction belt
drive. Checking the head pressure and adjusting the vertical guide rods is part of the
machine set-up process and should be part of a regular maintenance routine. Failure to
keep the head pressure within is recommended limits (75 to 85 pounds) can cause
problems with the machine’s performance. It is important to be able to recognize, and
correct, the signs of low or high head pressure before permanent damage is done to
your machine.
If there is not enough head pressure, the sensors that monitor whether the workpiece is
inserted correctly will not operate properly. If this happens then the message “Please
Insert Board” may persist on the LCD. Other signs of low head pressure are sandpaper
belt roll-up and board tracking issues. There are several main reasons that the head
pressure may be low:
• Insufficient lubrication on the vertical guide rods or the vertical leadscrews.
• Misalignment in the vertical guide rods.
• Poor mesh on the gears that drive the vertical leadscrews and move the head up
and down.
Signs that there is too much head pressure include a slow or unresponsive belt drive
and a clutch that is difficult to get to click. You can actually hear the base drive
struggling in many cases when it is overloaded and can break the drive gears if it is not
repaired. The reasons for excessive head pressure include:
• Lack of grease in the clutch.
• Very hot temperatures (100+ degrees) can cause part interference issues because
of thermal expansion.
FIGURE 1: HEAD VIEW SHOWING COMPRESSION ROLLERS
Head
Compression Rollers
CarveWright System Service – Adjusting the Head Pressure (Rev 1.7) 09/30/09 2
Checking the Head Pressure:
Checking the head pressure is very easy using a standard bathroom scale.
1. Before starting, make sure that the sliding plate is moved all the way to the far
side of the machine and is out of the way of the scale.
2. Place the scale on the traction drive exactly like a regular workpiece. Orient the
scale so that the measurement display is facing the keypad and position the top
head rollers (mounted on the underside of the head) directly over the scale
footpads.
3. Crank the head down and make sure to rotate the crank at least two revolutions
after the clicking begins to verify proper loading.
4. Read the scale measurement and repeat several times. The proper head loading
should be between 75 and 85 pounds.
Adjusting the Head Pressure (Out of Limits Low)
If the head loading is lower than 75 pounds, it is most likely caused by insufficient
lubrication of the four vertical corner posts or the two vertical leadscrews. Wipe all
residue off these parts and apply a thin film of White Lithium Grease to each. Crank the
head up and down several times so as to spread the grease evenly along the sliding
surfaces.
If lubricating the vertical guide rods does not resolve the low head pressure reading,
then you will want to realign them. The vertical guide rods are located at the four
corners of the machine and are the rails upon which the head of the machine rides up
and down. If these vertical guide rods are shifted out of alignment the head may bind
when lowered, and the pressure put on the workpiece by the compression rollers may
be too low for optimum operation. These vertical guide rods can be knocked out of
alignment during shipping or when the machine is moved.
In order to adjust the vertical guide rods you will need the following tools:
• #2 Phillips screwdriver or power drill with #2 screw bit
• 10mm socket, socket wrench, and 3” extension
1. Ready the machine. Unplug the machine from the power outlet and place it on a
stable work platform. Raise the head up several inches for best access. Move the
Z-truck to the very top of its travel (until it reaches the hard stop) so that the flexshaft
support tube protrudes from the head cover (See Figure 2).
CarveWright System Service – Adjusting the Head Pressure (Rev 1.7) 09/30/09 3
2. Detach the flexshaft from the top of the Z-truck: The flexshaft assembly is
retained by a ball detent located in the flexshaft receptacle (See Figure 3). Firmly
grasp the flexshaft support tube while reaching under the clear front cover with your
other hand to grab the Z-truck. Pull up firmly on the flexshaft support tube and twist
slightly while bracing the Z-truck. DO NOT PULL ON THE SHEATH. The flexshaft
will pop out of the detent. Wrap the end of the flexshaft in tape so that the core will
not fall out and lay the detached flexshaft end to the side.
3. Remove the bottom cover. Carefully lay the machine on its back with the dust
collection port facing down. Remove the 12 screws securing the black sheet metal
cover onto the base (four of which are located in the rubber feet) and remove it.
FIGURE 1: EXTERIOR VIEW OF THE FLEXSHAFT AND HEAD COVERS
FIGURE 3: VIEW OF THE FLEXSHAFT CONNECTION TO THE Z-TRUCK
Flexshaft Support Tube
Flexshaft Receptacle
End Of Flexshaft
Support Tube
Ball Detent
Z-Truck
Flexshaft Support Tube
Flexshaft Assembly
Clear Front Cover
CarveWright System Service – Adjusting the Head Pressure (Rev 1.7) 09/30/09 4
4. Check to see if the tie rod between the two leadscrews has sufficient play.
While the machine is still on its back, locate the leadscrew tie rod. This tie rod (with
bevel gears) connects the two leadscrews on either side of the machine. The
leadscrews drive the head up and down as the crank handle is turned. Grab the
tierod and verify that there is side to side play in the rod. The amount of play will
vary between machines, but the important thing to note is that there is some side to
side play. The play should be minimal but apparent. If the rod is locked side to side
turn the crank handle one full turn and try again. If the rod is still locked in place
please contact CarveWright technical support (713-473-6572) for additional
instructions.
5. Return the machine to its upright position. Be careful to not pinch any of the
base cables between the casting and the table. Crank the head down to within 1” of
the sandpaper belts.
FIGURE 4: REMOVAL OF THE
BOTTOM COVER
FIGURE 5: LOCATION OF THE LEADSCREW TIE ROD
Bottom Closeout Cover
Cover Screw (12X)
Rubber Foot (4X)
Louvers (Facing into Machine)
Controller Box
Power Supply
Leadscrew Tie Rod
Tie Rod Bevel Gear
Leadscrew Bevel Gear
CarveWright System Service – Adjusting the Head Pressure (Rev 1.7) 09/30/09 5
6. Loosen the screws securing the top of the four vertical guide rods. Using a
10mm socket, loosen all four bolts attaching the vertical guide rods to the top of the
side panels. LOOSEN 1 to 2 TURNS ONLY - DO NOT REMOVE SCREWS.
7. Loosen one set of bottom screws securing the vertical guide rods. Slide one
end of the machine 4 inches off the edge of the bench. It does not matter if it is the
side with the keypad or the side without. This will give you sufficient room to reach
to screws attaching the bottom of the vertical guide rods to the base of the machine
on the overhanging side (see Figure 7). Loosen both screws attaching the bottom of
the vertical guide rods to the base of the machine with the 10mm socket. LOOSEN
1 to 2 TURNS ONLY - DO NOT REMOVE SCREWS. Now all four screws (top and
bottom) attaching the two vertical guide rods on the overhanging side are loose. This
allows the head to naturally set the correct spacing for these two guide rods.
FIGURE 6: LOCATION OF TOP VERTICAL GUIDE ROD SCREWS
FIGURE 7: LOCATION OF BOTTOM VERTICAL GUIDE ROD SCREWS
Top Guide Rod Screw
Screw
Location
Screw
Location
Screw
Location
Screw
Location
CarveWright System Service – Adjusting the Head Pressure (Rev 1.7) 09/30/09 6
8. Tighten the two bottom screws.
9. Rotate machine 180 degrees to where the other side of the machine is overhanging
the bench. Repeat Step 8-9 for this side of the machine.
10. Tighten the screws securing the vertical guide rods: Crank head up to
approximately the center of travel and tighten the four top 10mm bolts.
11. Re-check head pressure using the procedure used in the Troubleshooting
section of your Operators Manual. If the head pressure still reads low, please
contact CarveWright technical support (713-473-6572) for additional instructions.
Reassembling the Machine
1. Replace the bottom cover. Replace the metal cover with the louvers pointing into
the machine (see Figure 4). Insert and tighten the 12 screws. The four rubber feet
are placed at the corners of the machine.
2. Prepare the flexshaft assembly for re-insertion into the machine: Gently pull
the protruding flexshaft core (with squared end) out of the sheath several inches.
Push the core back into the sheath and make sure that it slips into, and engages, the
cutting motor. It will drop into the receptacle on the motor side about 5/8ths of an
inch. Turn the core by hand and feel for resistance of the motor. If the shaft spins
without resistance, push the core inward while rotating until it drops into the slot and
engages the motor.
3. Insert the flexshaft into cutting head: Looking through the slot in the top cover,
locate the flexshaft receptacle on the top of the Z-truck. Inside the receptacle there
is a square recess that mates with the exposed square end of the flexshaft core.
Turn the chuck on the bottom of the cutting head (open the safety cover for access)
until the square core end can be inserted into the recess. Press the flex shaft all the
way down into its receptacle. A click will be heard and felt as the shaft snaps into
place.
Adjusting the Head Pressure (Out of Limits High)
If the head loading is higher than 85 pounds, it is most likely caused by insufficient
lubrication in the clutch. Remove the Crank Handle Assembly using a Phillips screw
driver. Make sure to remove the clutch spring as well.
FIGURE 8: REMOVING THE CRANK HANDLE
(MACHINE NOT SHOWN)
Handle Screw Clutch Spring
Crank Handle Assembly
Clutch Force Adjustment Spacer(s)
Clutch Plate (Internal)
CarveWright System Service – Adjusting the Head Pressure (Rev 1.7) 09/30/09 7
Using a spray applicator of white Lithium grease, generously coat the internal clutch
plate and surrounding parts through the hole once occupied by the handle. Make sure
to get the grease as far into the hole as possible and apply liberally.
Reassemble the clutch handle and crank. The handle has flats that need to align with
flats on the clutch plate. As you tighten the handle screw, make sure the handle lines
up correctly. You will feel it “fall” into the center hole of the clutch plate when the flats
align.
Crank the head all the way down onto a board and keep turning so as to spread the
grease on the friction surfaces. Re-measure the head pressure. If the head pressure
still reads high, please contact CarveWright technical support (713-473-6572) for
additional instructions.
FIGURE 9: ORIENTING THE CRANK HANDLE
Alignment Flat
Alignment Flat
Clutch Plate
We are attempting to
get grease on this face

[cestout]

Squirt some of the stuff - spray lithium grease - into clutch. position the crank so it hangs straight down and remove it. Spray the grease in there and replace the crank. I have to do this occasionally to my C machine, but never the B, but I have replaced the clutch plate in the B twice. The C gets so the doesn't click, just cranks down.
Clint